1LD(1) GNU Development Tools LD(1)
2
6 ld - The GNU linker
7
9 ld [options] objfile ...
10
12 ld combines a number of object and archive files, relocates their data
13 and ties up symbol references. Usually the last step in compiling a
14 program is to run ld.
15 ld accepts Linker Command Language files written in a superset of
17 AT&T's Link Editor Command Language syntax, to provide explicit and
18 total control over the linking process.
19 This man page does not describe the command language; see the ld entry
21 in "info" for full details on the command language and on other aspects
22 of the GNU linker.
23 This version of ld uses the general purpose BFD libraries to operate on
25 object files. This allows ld to read, combine, and write object files
26 in many different formats---for example, COFF or "a.out". Different
27 formats may be linked together to produce any available kind of object
28 file.
29 Aside from its flexibility, the GNU linker is more helpful than other
31 linkers in providing diagnostic information. Many linkers abandon
32 execution immediately upon encountering an error; whenever possible, ld
33 continues executing, allowing you to identify other errors (or, in some
34 cases, to get an output file in spite of the error).
35 The GNU linker ld is meant to cover a broad range of situations, and to
37 be as compatible as possible with other linkers. As a result, you have
38 many choices to control its behavior.
39
41 The linker supports a plethora of command-line options, but in actual
42 practice few of them are used in any particular context. For instance,
43 a frequent use of ld is to link standard Unix object files on a
44 standard, supported Unix system. On such a system, to link a file
45 "hello.o":
46 ld -o <output> /lib/crt0.o hello.o -lc
48 This tells ld to produce a file called output as the result of linking
50 the file "/lib/crt0.o" with "hello.o" and the library "libc.a", which
51 will come from the standard search directories. (See the discussion of
52 the -l option below.)
53 Some of the command-line options to ld may be specified at any point in
55 the command line. However, options which refer to files, such as -l or
56 -T, cause the file to be read at the point at which the option appears
57 in the command line, relative to the object files and other file
58 options. Repeating non-file options with a different argument will
59 either have no further effect, or override prior occurrences (those
60 further to the left on the command line) of that option. Options which
61 may be meaningfully specified more than once are noted in the
62 descriptions below.
63 Non-option arguments are object files or archives which are to be
65 linked together. They may follow, precede, or be mixed in with
66 command-line options, except that an object file argument may not be
67 placed between an option and its argument.
68 Usually the linker is invoked with at least one object file, but you
70 can specify other forms of binary input files using -l, -R, and the
71 script command language. If no binary input files at all are
72 specified, the linker does not produce any output, and issues the
73 message No input files.
74 If the linker cannot recognize the format of an object file, it will
76 assume that it is a linker script. A script specified in this way
77 augments the main linker script used for the link (either the default
78 linker script or the one specified by using -T). This feature permits
79 the linker to link against a file which appears to be an object or an
80 archive, but actually merely defines some symbol values, or uses
81 "INPUT" or "GROUP" to load other objects. Specifying a script in this
82 way merely augments the main linker script, with the extra commands
83 placed after the main script; use the -T option to replace the default
84 linker script entirely, but note the effect of the "INSERT" command.
85 For options whose names are a single letter, option arguments must
87 either follow the option letter without intervening whitespace, or be
88 given as separate arguments immediately following the option that
89 requires them.
90 For options whose names are multiple letters, either one dash or two
92 can precede the option name; for example, -trace-symbol and
93 --trace-symbol are equivalent. Note---there is one exception to this
94 rule. Multiple letter options that start with a lower case 'o' can
95 only be preceded by two dashes. This is to reduce confusion with the
96 -o option. So for example -omagic sets the output file name to magic
97 whereas --omagic sets the NMAGIC flag on the output.
98 Arguments to multiple-letter options must either be separated from the
100 option name by an equals sign, or be given as separate arguments
101 immediately following the option that requires them. For example,
102 --trace-symbol foo and --trace-symbol=foo are equivalent. Unique
103 abbreviations of the names of multiple-letter options are accepted.
104 Note---if the linker is being invoked indirectly, via a compiler driver
106 (e.g. gcc) then all the linker command line options should be prefixed
107 by -Wl, (or whatever is appropriate for the particular compiler driver)
108 like this:
109 gcc -Wl,--start-group foo.o bar.o -Wl,--end-group
111 This is important, because otherwise the compiler driver program may
113 silently drop the linker options, resulting in a bad link. Confusion
114 may also arise when passing options that require values through a
115 driver, as the use of a space between option and argument acts as a
116 separator, and causes the driver to pass only the option to the linker
117 and the argument to the compiler. In this case, it is simplest to use
118 the joined forms of both single- and multiple-letter options, such as:
119 gcc foo.o bar.o -Wl,-eENTRY -Wl,-Map=a.map
121 Here is a table of the generic command line switches accepted by the
123 GNU linker:
124 @file
126 Read command-line options from file. The options read are inserted
127 in place of the original @file option. If file does not exist, or
128 cannot be read, then the option will be treated literally, and not
129 removed.
130 Options in file are separated by whitespace. A whitespace
132 character may be included in an option by surrounding the entire
133 option in either single or double quotes. Any character (including
134 a backslash) may be included by prefixing the character to be
135 included with a backslash. The file may itself contain additional
136 @file options; any such options will be processed recursively.
137 -a keyword
139 This option is supported for HP/UX compatibility. The keyword
140 argument must be one of the strings archive, shared, or default.
141 -aarchive is functionally equivalent to -Bstatic, and the other two
142 keywords are functionally equivalent to -Bdynamic. This option may
143 be used any number of times.
144 --audit AUDITLIB
146 Adds AUDITLIB to the "DT_AUDIT" entry of the dynamic section.
147 AUDITLIB is not checked for existence, nor will it use the
148 DT_SONAME specified in the library. If specified multiple times
149 "DT_AUDIT" will contain a colon separated list of audit interfaces
150 to use. If the linker finds an object with an audit entry while
151 searching for shared libraries, it will add a corresponding
152 "DT_DEPAUDIT" entry in the output file. This option is only
153 meaningful on ELF platforms supporting the rtld-audit interface.
154 -A architecture
156 --architecture=architecture
157 In the current release of ld, this option is useful only for the
158 Intel 960 family of architectures. In that ld configuration, the
159 architecture argument identifies the particular architecture in the
160 960 family, enabling some safeguards and modifying the archive-
161 library search path.
162 Future releases of ld may support similar functionality for other
164 architecture families.
165 -b input-format
167 --format=input-format
168 ld may be configured to support more than one kind of object file.
169 If your ld is configured this way, you can use the -b option to
170 specify the binary format for input object files that follow this
171 option on the command line. Even when ld is configured to support
172 alternative object formats, you don't usually need to specify this,
173 as ld should be configured to expect as a default input format the
174 most usual format on each machine. input-format is a text string,
175 the name of a particular format supported by the BFD libraries.
176 (You can list the available binary formats with objdump -i.)
177 You may want to use this option if you are linking files with an
179 unusual binary format. You can also use -b to switch formats
180 explicitly (when linking object files of different formats), by
181 including -b input-format before each group of object files in a
182 particular format.
183 The default format is taken from the environment variable
185 "GNUTARGET".
186 You can also define the input format from a script, using the
188 command "TARGET";
189 -c MRI-commandfile
191 --mri-script=MRI-commandfile
192 For compatibility with linkers produced by MRI, ld accepts script
193 files written in an alternate, restricted command language,
194 described in the MRI Compatible Script Files section of GNU ld
195 documentation. Introduce MRI script files with the option -c; use
196 the -T option to run linker scripts written in the general-purpose
197 ld scripting language. If MRI-cmdfile does not exist, ld looks for
198 it in the directories specified by any -L options.
199 -d
201 -dc
202 -dp These three options are equivalent; multiple forms are supported
203 for compatibility with other linkers. They assign space to common
204 symbols even if a relocatable output file is specified (with -r).
205 The script command "FORCE_COMMON_ALLOCATION" has the same effect.
206 --depaudit AUDITLIB
208 -P AUDITLIB
209 Adds AUDITLIB to the "DT_DEPAUDIT" entry of the dynamic section.
210 AUDITLIB is not checked for existence, nor will it use the
211 DT_SONAME specified in the library. If specified multiple times
212 "DT_DEPAUDIT" will contain a colon separated list of audit
213 interfaces to use. This option is only meaningful on ELF platforms
214 supporting the rtld-audit interface. The -P option is provided for
215 Solaris compatibility.
216 -e entry
218 --entry=entry
219 Use entry as the explicit symbol for beginning execution of your
220 program, rather than the default entry point. If there is no
221 symbol named entry, the linker will try to parse entry as a number,
222 and use that as the entry address (the number will be interpreted
223 in base 10; you may use a leading 0x for base 16, or a leading 0
224 for base 8).
225 --exclude-libs lib,lib,...
227 Specifies a list of archive libraries from which symbols should not
228 be automatically exported. The library names may be delimited by
229 commas or colons. Specifying "--exclude-libs ALL" excludes symbols
230 in all archive libraries from automatic export. This option is
231 available only for the i386 PE targeted port of the linker and for
232 ELF targeted ports. For i386 PE, symbols explicitly listed in a
233 .def file are still exported, regardless of this option. For ELF
234 targeted ports, symbols affected by this option will be treated as
235 hidden.
236 --exclude-modules-for-implib module,module,...
238 Specifies a list of object files or archive members, from which
239 symbols should not be automatically exported, but which should be
240 copied wholesale into the import library being generated during the
241 link. The module names may be delimited by commas or colons, and
242 must match exactly the filenames used by ld to open the files; for
243 archive members, this is simply the member name, but for object
244 files the name listed must include and match precisely any path
245 used to specify the input file on the linker's command-line. This
246 option is available only for the i386 PE targeted port of the
247 linker. Symbols explicitly listed in a .def file are still
248 exported, regardless of this option.
249 -E
251 --export-dynamic
252 --no-export-dynamic
253 When creating a dynamically linked executable, using the -E option
254 or the --export-dynamic option causes the linker to add all symbols
255 to the dynamic symbol table. The dynamic symbol table is the set
256 of symbols which are visible from dynamic objects at run time.
257 If you do not use either of these options (or use the
259 --no-export-dynamic option to restore the default behavior), the
260 dynamic symbol table will normally contain only those symbols which
261 are referenced by some dynamic object mentioned in the link.
262 If you use "dlopen" to load a dynamic object which needs to refer
264 back to the symbols defined by the program, rather than some other
265 dynamic object, then you will probably need to use this option when
266 linking the program itself.
267 You can also use the dynamic list to control what symbols should be
269 added to the dynamic symbol table if the output format supports it.
270 See the description of --dynamic-list.
271 Note that this option is specific to ELF targeted ports. PE
273 targets support a similar function to export all symbols from a DLL
274 or EXE; see the description of --export-all-symbols below.
275 -EB Link big-endian objects. This affects the default output format.
277 -EL Link little-endian objects. This affects the default output
279 format.
280 -f name
282 --auxiliary=name
283 When creating an ELF shared object, set the internal DT_AUXILIARY
284 field to the specified name. This tells the dynamic linker that
285 the symbol table of the shared object should be used as an
286 auxiliary filter on the symbol table of the shared object name.
287 If you later link a program against this filter object, then, when
289 you run the program, the dynamic linker will see the DT_AUXILIARY
290 field. If the dynamic linker resolves any symbols from the filter
291 object, it will first check whether there is a definition in the
292 shared object name. If there is one, it will be used instead of
293 the definition in the filter object. The shared object name need
294 not exist. Thus the shared object name may be used to provide an
295 alternative implementation of certain functions, perhaps for
296 debugging or for machine specific performance.
297 This option may be specified more than once. The DT_AUXILIARY
299 entries will be created in the order in which they appear on the
300 command line.
301 -F name
303 --filter=name
304 When creating an ELF shared object, set the internal DT_FILTER
305 field to the specified name. This tells the dynamic linker that
306 the symbol table of the shared object which is being created should
307 be used as a filter on the symbol table of the shared object name.
308 If you later link a program against this filter object, then, when
310 you run the program, the dynamic linker will see the DT_FILTER
311 field. The dynamic linker will resolve symbols according to the
312 symbol table of the filter object as usual, but it will actually
313 link to the definitions found in the shared object name. Thus the
314 filter object can be used to select a subset of the symbols
315 provided by the object name.
316 Some older linkers used the -F option throughout a compilation
318 toolchain for specifying object-file format for both input and
319 output object files. The GNU linker uses other mechanisms for this
320 purpose: the -b, --format, --oformat options, the "TARGET" command
321 in linker scripts, and the "GNUTARGET" environment variable. The
322 GNU linker will ignore the -F option when not creating an ELF
323 shared object.
324 -fini=name
326 When creating an ELF executable or shared object, call NAME when
327 the executable or shared object is unloaded, by setting DT_FINI to
328 the address of the function. By default, the linker uses "_fini"
329 as the function to call.
330 -g Ignored. Provided for compatibility with other tools.
332 -G value
334 --gpsize=value
335 Set the maximum size of objects to be optimized using the GP
336 register to size. This is only meaningful for object file formats
337 such as MIPS ECOFF which supports putting large and small objects
338 into different sections. This is ignored for other object file
339 formats.
340 -h name
342 -soname=name
343 When creating an ELF shared object, set the internal DT_SONAME
344 field to the specified name. When an executable is linked with a
345 shared object which has a DT_SONAME field, then when the executable
346 is run the dynamic linker will attempt to load the shared object
347 specified by the DT_SONAME field rather than the using the file
348 name given to the linker.
349 -i Perform an incremental link (same as option -r).
351 -init=name
353 When creating an ELF executable or shared object, call NAME when
354 the executable or shared object is loaded, by setting DT_INIT to
355 the address of the function. By default, the linker uses "_init"
356 as the function to call.
357 -l namespec
359 --library=namespec
360 Add the archive or object file specified by namespec to the list of
361 files to link. This option may be used any number of times. If
362 namespec is of the form :filename, ld will search the library path
363 for a file called filename, otherwise it will search the library
364 path for a file called libnamespec.a.
365 On systems which support shared libraries, ld may also search for
367 files other than libnamespec.a. Specifically, on ELF and SunOS
368 systems, ld will search a directory for a library called
369 libnamespec.so before searching for one called libnamespec.a. (By
370 convention, a ".so" extension indicates a shared library.) Note
371 that this behavior does not apply to :filename, which always
372 specifies a file called filename.
373 The linker will search an archive only once, at the location where
375 it is specified on the command line. If the archive defines a
376 symbol which was undefined in some object which appeared before the
377 archive on the command line, the linker will include the
378 appropriate file(s) from the archive. However, an undefined symbol
379 in an object appearing later on the command line will not cause the
380 linker to search the archive again.
381 See the -( option for a way to force the linker to search archives
383 multiple times.
384 You may list the same archive multiple times on the command line.
386 This type of archive searching is standard for Unix linkers.
388 However, if you are using ld on AIX, note that it is different from
389 the behaviour of the AIX linker.
390 -L searchdir
392 --library-path=searchdir
393 Add path searchdir to the list of paths that ld will search for
394 archive libraries and ld control scripts. You may use this option
395 any number of times. The directories are searched in the order in
396 which they are specified on the command line. Directories
397 specified on the command line are searched before the default
398 directories. All -L options apply to all -l options, regardless of
399 the order in which the options appear. -L options do not affect
400 how ld searches for a linker script unless -T option is specified.
401 If searchdir begins with "=", then the "=" will be replaced by the
403 sysroot prefix, a path specified when the linker is configured.
404 The default set of paths searched (without being specified with -L)
406 depends on which emulation mode ld is using, and in some cases also
407 on how it was configured.
408 The paths can also be specified in a link script with the
410 "SEARCH_DIR" command. Directories specified this way are searched
411 at the point in which the linker script appears in the command
412 line.
413 -m emulation
415 Emulate the emulation linker. You can list the available
416 emulations with the --verbose or -V options.
417 If the -m option is not used, the emulation is taken from the
419 "LDEMULATION" environment variable, if that is defined.
420 Otherwise, the default emulation depends upon how the linker was
422 configured.
423 -M
425 --print-map
426 Print a link map to the standard output. A link map provides
427 information about the link, including the following:
428 · Where object files are mapped into memory.
430 · How common symbols are allocated.
432 · All archive members included in the link, with a mention of the
434 symbol which caused the archive member to be brought in.
435 · The values assigned to symbols.
437 Note - symbols whose values are computed by an expression which
439 involves a reference to a previous value of the same symbol may
440 not have correct result displayed in the link map. This is
441 because the linker discards intermediate results and only
442 retains the final value of an expression. Under such
443 circumstances the linker will display the final value enclosed
444 by square brackets. Thus for example a linker script
445 containing:
446 foo = 1
448 foo = foo * 4
449 foo = foo + 8
450 will produce the following output in the link map if the -M
452 option is used:
453 0x00000001 foo = 0x1
455 [0x0000000c] foo = (foo * 0x4)
456 [0x0000000c] foo = (foo + 0x8)
457 See Expressions for more information about expressions in
459 linker scripts.
460 -n
462 --nmagic
463 Turn off page alignment of sections, and mark the output as
464 "NMAGIC" if possible.
465 -N
467 --omagic
468 Set the text and data sections to be readable and writable. Also,
469 do not page-align the data segment, and disable linking against
470 shared libraries. If the output format supports Unix style magic
471 numbers, mark the output as "OMAGIC". Note: Although a writable
472 text section is allowed for PE-COFF targets, it does not conform to
473 the format specification published by Microsoft.
474 --no-omagic
476 This option negates most of the effects of the -N option. It sets
477 the text section to be read-only, and forces the data segment to be
478 page-aligned. Note - this option does not enable linking against
479 shared libraries. Use -Bdynamic for this.
480 -o output
482 --output=output
483 Use output as the name for the program produced by ld; if this
484 option is not specified, the name a.out is used by default. The
485 script command "OUTPUT" can also specify the output file name.
486 -O level
488 If level is a numeric values greater than zero ld optimizes the
489 output. This might take significantly longer and therefore
490 probably should only be enabled for the final binary. At the
491 moment this option only affects ELF shared library generation.
492 Future releases of the linker may make more use of this option.
493 Also currently there is no difference in the linker's behaviour for
494 different non-zero values of this option. Again this may change
495 with future releases.
496 -q
498 --emit-relocs
499 Leave relocation sections and contents in fully linked executables.
500 Post link analysis and optimization tools may need this information
501 in order to perform correct modifications of executables. This
502 results in larger executables.
503 This option is currently only supported on ELF platforms.
505 --force-dynamic
507 Force the output file to have dynamic sections. This option is
508 specific to VxWorks targets.
509 -r
511 --relocatable
512 Generate relocatable output---i.e., generate an output file that
513 can in turn serve as input to ld. This is often called partial
514 linking. As a side effect, in environments that support standard
515 Unix magic numbers, this option also sets the output file's magic
516 number to "OMAGIC". If this option is not specified, an absolute
517 file is produced. When linking C++ programs, this option will not
518 resolve references to constructors; to do that, use -Ur.
519 When an input file does not have the same format as the output
521 file, partial linking is only supported if that input file does not
522 contain any relocations. Different output formats can have further
523 restrictions; for example some "a.out"-based formats do not support
524 partial linking with input files in other formats at all.
525 This option does the same thing as -i.
527 -R filename
529 --just-symbols=filename
530 Read symbol names and their addresses from filename, but do not
531 relocate it or include it in the output. This allows your output
532 file to refer symbolically to absolute locations of memory defined
533 in other programs. You may use this option more than once.
534 For compatibility with other ELF linkers, if the -R option is
536 followed by a directory name, rather than a file name, it is
537 treated as the -rpath option.
538 -s
540 --strip-all
541 Omit all symbol information from the output file.
542 -S
544 --strip-debug
545 Omit debugger symbol information (but not all symbols) from the
546 output file.
547 -t
549 --trace
550 Print the names of the input files as ld processes them.
551 -T scriptfile
553 --script=scriptfile
554 Use scriptfile as the linker script. This script replaces ld's
555 default linker script (rather than adding to it), so commandfile
556 must specify everything necessary to describe the output file.
557 If scriptfile does not exist in the current directory, "ld" looks
558 for it in the directories specified by any preceding -L options.
559 Multiple -T options accumulate.
560 -dT scriptfile
562 --default-script=scriptfile
563 Use scriptfile as the default linker script.
564 This option is similar to the --script option except that
566 processing of the script is delayed until after the rest of the
567 command line has been processed. This allows options placed after
568 the --default-script option on the command line to affect the
569 behaviour of the linker script, which can be important when the
570 linker command line cannot be directly controlled by the user. (eg
571 because the command line is being constructed by another tool, such
572 as gcc).
573 -u symbol
575 --undefined=symbol
576 Force symbol to be entered in the output file as an undefined
577 symbol. Doing this may, for example, trigger linking of additional
578 modules from standard libraries. -u may be repeated with different
579 option arguments to enter additional undefined symbols. This
580 option is equivalent to the "EXTERN" linker script command.
581 -Ur For anything other than C++ programs, this option is equivalent to
583 -r: it generates relocatable output---i.e., an output file that can
584 in turn serve as input to ld. When linking C++ programs, -Ur does
585 resolve references to constructors, unlike -r. It does not work to
586 use -Ur on files that were themselves linked with -Ur; once the
587 constructor table has been built, it cannot be added to. Use -Ur
588 only for the last partial link, and -r for the others.
589 --unique[=SECTION]
591 Creates a separate output section for every input section matching
592 SECTION, or if the optional wildcard SECTION argument is missing,
593 for every orphan input section. An orphan section is one not
594 specifically mentioned in a linker script. You may use this option
595 multiple times on the command line; It prevents the normal merging
596 of input sections with the same name, overriding output section
597 assignments in a linker script.
598 -v
600 --version
601 -V Display the version number for ld. The -V option also lists the
602 supported emulations.
603 -x
605 --discard-all
606 Delete all local symbols.
607 -X
609 --discard-locals
610 Delete all temporary local symbols. (These symbols start with
611 system-specific local label prefixes, typically .L for ELF systems
612 or L for traditional a.out systems.)
613 -y symbol
615 --trace-symbol=symbol
616 Print the name of each linked file in which symbol appears. This
617 option may be given any number of times. On many systems it is
618 necessary to prepend an underscore.
619 This option is useful when you have an undefined symbol in your
621 link but don't know where the reference is coming from.
622 -Y path
624 Add path to the default library search path. This option exists
625 for Solaris compatibility.
626 -z keyword
628 The recognized keywords are:
629 combreloc
631 Combines multiple reloc sections and sorts them to make dynamic
632 symbol lookup caching possible.
633 defs
635 Disallows undefined symbols in object files. Undefined symbols
636 in shared libraries are still allowed.
637 execstack
639 Marks the object as requiring executable stack.
640 initfirst
642 This option is only meaningful when building a shared object.
643 It marks the object so that its runtime initialization will
644 occur before the runtime initialization of any other objects
645 brought into the process at the same time. Similarly the
646 runtime finalization of the object will occur after the runtime
647 finalization of any other objects.
648 interpose
650 Marks the object that its symbol table interposes before all
651 symbols but the primary executable.
652 lazy
654 When generating an executable or shared library, mark it to
655 tell the dynamic linker to defer function call resolution to
656 the point when the function is called (lazy binding), rather
657 than at load time. Lazy binding is the default.
658 loadfltr
660 Marks the object that its filters be processed immediately at
661 runtime.
662 muldefs
664 Allows multiple definitions.
665 nocombreloc
667 Disables multiple reloc sections combining.
668 nocopyreloc
670 Disables production of copy relocs.
671 nodefaultlib
673 Marks the object that the search for dependencies of this
674 object will ignore any default library search paths.
675 nodelete
677 Marks the object shouldn't be unloaded at runtime.
678 nodlopen
680 Marks the object not available to "dlopen".
681 nodump
683 Marks the object can not be dumped by "dldump".
684 noexecstack
686 Marks the object as not requiring executable stack.
687 norelro
689 Don't create an ELF "PT_GNU_RELRO" segment header in the
690 object.
691 now When generating an executable or shared library, mark it to
693 tell the dynamic linker to resolve all symbols when the program
694 is started, or when the shared library is linked to using
695 dlopen, instead of deferring function call resolution to the
696 point when the function is first called.
697 origin
699 Marks the object may contain $ORIGIN.
700 relro
702 Create an ELF "PT_GNU_RELRO" segment header in the object.
703 max-page-size=value
705 Set the emulation maximum page size to value.
706 common-page-size=value
708 Set the emulation common page size to value.
709 Other keywords are ignored for Solaris compatibility.
711 -( archives -)
713 --start-group archives --end-group
714 The archives should be a list of archive files. They may be either
715 explicit file names, or -l options.
716 The specified archives are searched repeatedly until no new
718 undefined references are created. Normally, an archive is searched
719 only once in the order that it is specified on the command line.
720 If a symbol in that archive is needed to resolve an undefined
721 symbol referred to by an object in an archive that appears later on
722 the command line, the linker would not be able to resolve that
723 reference. By grouping the archives, they all be searched
724 repeatedly until all possible references are resolved.
725 Using this option has a significant performance cost. It is best
727 to use it only when there are unavoidable circular references
728 between two or more archives.
729 --accept-unknown-input-arch
731 --no-accept-unknown-input-arch
732 Tells the linker to accept input files whose architecture cannot be
733 recognised. The assumption is that the user knows what they are
734 doing and deliberately wants to link in these unknown input files.
735 This was the default behaviour of the linker, before release 2.14.
736 The default behaviour from release 2.14 onwards is to reject such
737 input files, and so the --accept-unknown-input-arch option has been
738 added to restore the old behaviour.
739 --as-needed
741 --no-as-needed
742 This option affects ELF DT_NEEDED tags for dynamic libraries
743 mentioned on the command line after the --as-needed option.
744 Normally the linker will add a DT_NEEDED tag for each dynamic
745 library mentioned on the command line, regardless of whether the
746 library is actually needed or not. --as-needed causes a DT_NEEDED
747 tag to only be emitted for a library that satisfies an undefined
748 symbol reference from a regular object file or, if the library is
749 not found in the DT_NEEDED lists of other libraries linked up to
750 that point, an undefined symbol reference from another dynamic
751 library. --no-as-needed restores the default behaviour.
752 --add-needed
754 --no-add-needed
755 These two options have been deprecated because of the similarity of
756 their names to the --as-needed and --no-as-needed options. They
757 have been replaced by --copy-dt-needed-entries and
758 --no-copy-dt-needed-entries.
759 -assert keyword
761 This option is ignored for SunOS compatibility.
762 -Bdynamic
764 -dy
765 -call_shared
766 Link against dynamic libraries. This is only meaningful on
767 platforms for which shared libraries are supported. This option is
768 normally the default on such platforms. The different variants of
769 this option are for compatibility with various systems. You may
770 use this option multiple times on the command line: it affects
771 library searching for -l options which follow it.
772 -Bgroup
774 Set the "DF_1_GROUP" flag in the "DT_FLAGS_1" entry in the dynamic
775 section. This causes the runtime linker to handle lookups in this
776 object and its dependencies to be performed only inside the group.
777 --unresolved-symbols=report-all is implied. This option is only
778 meaningful on ELF platforms which support shared libraries.
779 -Bstatic
781 -dn
782 -non_shared
783 -static
784 Do not link against shared libraries. This is only meaningful on
785 platforms for which shared libraries are supported. The different
786 variants of this option are for compatibility with various systems.
787 You may use this option multiple times on the command line: it
788 affects library searching for -l options which follow it. This
789 option also implies --unresolved-symbols=report-all. This option
790 can be used with -shared. Doing so means that a shared library is
791 being created but that all of the library's external references
792 must be resolved by pulling in entries from static libraries.
793 -Bsymbolic
795 When creating a shared library, bind references to global symbols
796 to the definition within the shared library, if any. Normally, it
797 is possible for a program linked against a shared library to
798 override the definition within the shared library. This option is
799 only meaningful on ELF platforms which support shared libraries.
800 -Bsymbolic-functions
802 When creating a shared library, bind references to global function
803 symbols to the definition within the shared library, if any. This
804 option is only meaningful on ELF platforms which support shared
805 libraries.
806 --dynamic-list=dynamic-list-file
808 Specify the name of a dynamic list file to the linker. This is
809 typically used when creating shared libraries to specify a list of
810 global symbols whose references shouldn't be bound to the
811 definition within the shared library, or creating dynamically
812 linked executables to specify a list of symbols which should be
813 added to the symbol table in the executable. This option is only
814 meaningful on ELF platforms which support shared libraries.
815 The format of the dynamic list is the same as the version node
817 without scope and node name. See VERSION for more information.
818 --dynamic-list-data
820 Include all global data symbols to the dynamic list.
821 --dynamic-list-cpp-new
823 Provide the builtin dynamic list for C++ operator new and delete.
824 It is mainly useful for building shared libstdc++.
825 --dynamic-list-cpp-typeinfo
827 Provide the builtin dynamic list for C++ runtime type
828 identification.
829 --check-sections
831 --no-check-sections
832 Asks the linker not to check section addresses after they have been
833 assigned to see if there are any overlaps. Normally the linker
834 will perform this check, and if it finds any overlaps it will
835 produce suitable error messages. The linker does know about, and
836 does make allowances for sections in overlays. The default
837 behaviour can be restored by using the command line switch
838 --check-sections. Section overlap is not usually checked for
839 relocatable links. You can force checking in that case by using
840 the --check-sections option.
841 --copy-dt-needed-entries
843 --no-copy-dt-needed-entries
844 This option affects the treatment of dynamic libraries referred to
845 by DT_NEEDED tags inside ELF dynamic libraries mentioned on the
846 command line. Normally the linker will add a DT_NEEDED tag to the
847 output binary for each library mentioned in a DT_NEEDED tag in an
848 input dynamic library. With --no-copy-dt-needed-entries specified
849 on the command line however any dynamic libraries that follow it
850 will have their DT_NEEDED entries ignored. The default behaviour
851 can be restored with --copy-dt-needed-entries.
852 This option also has an effect on the resolution of symbols in
854 dynamic libraries. With the default setting dynamic libraries
855 mentioned on the command line will be recursively searched,
856 following their DT_NEEDED tags to other libraries, in order to
857 resolve symbols required by the output binary. With
858 --no-copy-dt-needed-entries specified however the searching of
859 dynamic libraries that follow it will stop with the dynamic library
860 itself. No DT_NEEDED links will be traversed to resolve symbols.
861 --cref
863 Output a cross reference table. If a linker map file is being
864 generated, the cross reference table is printed to the map file.
865 Otherwise, it is printed on the standard output.
866 The format of the table is intentionally simple, so that it may be
868 easily processed by a script if necessary. The symbols are printed
869 out, sorted by name. For each symbol, a list of file names is
870 given. If the symbol is defined, the first file listed is the
871 location of the definition. The remaining files contain references
872 to the symbol.
873 --no-define-common
875 This option inhibits the assignment of addresses to common symbols.
876 The script command "INHIBIT_COMMON_ALLOCATION" has the same effect.
877 The --no-define-common option allows decoupling the decision to
879 assign addresses to Common symbols from the choice of the output
880 file type; otherwise a non-Relocatable output type forces assigning
881 addresses to Common symbols. Using --no-define-common allows
882 Common symbols that are referenced from a shared library to be
883 assigned addresses only in the main program. This eliminates the
884 unused duplicate space in the shared library, and also prevents any
885 possible confusion over resolving to the wrong duplicate when there
886 are many dynamic modules with specialized search paths for runtime
887 symbol resolution.
888 --defsym=symbol=expression
890 Create a global symbol in the output file, containing the absolute
891 address given by expression. You may use this option as many times
892 as necessary to define multiple symbols in the command line. A
893 limited form of arithmetic is supported for the expression in this
894 context: you may give a hexadecimal constant or the name of an
895 existing symbol, or use "+" and "-" to add or subtract hexadecimal
896 constants or symbols. If you need more elaborate expressions,
897 consider using the linker command language from a script. Note:
898 there should be no white space between symbol, the equals sign
899 ("="), and expression.
900 --demangle[=style]
902 --no-demangle
903 These options control whether to demangle symbol names in error
904 messages and other output. When the linker is told to demangle, it
905 tries to present symbol names in a readable fashion: it strips
906 leading underscores if they are used by the object file format, and
907 converts C++ mangled symbol names into user readable names.
908 Different compilers have different mangling styles. The optional
909 demangling style argument can be used to choose an appropriate
910 demangling style for your compiler. The linker will demangle by
911 default unless the environment variable COLLECT_NO_DEMANGLE is set.
912 These options may be used to override the default.
913 -Ifile
915 --dynamic-linker=file
916 Set the name of the dynamic linker. This is only meaningful when
917 generating dynamically linked ELF executables. The default dynamic
918 linker is normally correct; don't use this unless you know what you
919 are doing.
920 --fatal-warnings
922 --no-fatal-warnings
923 Treat all warnings as errors. The default behaviour can be
924 restored with the option --no-fatal-warnings.
925 --force-exe-suffix
927 Make sure that an output file has a .exe suffix.
928 If a successfully built fully linked output file does not have a
930 ".exe" or ".dll" suffix, this option forces the linker to copy the
931 output file to one of the same name with a ".exe" suffix. This
932 option is useful when using unmodified Unix makefiles on a
933 Microsoft Windows host, since some versions of Windows won't run an
934 image unless it ends in a ".exe" suffix.
935 --gc-sections
937 --no-gc-sections
938 Enable garbage collection of unused input sections. It is ignored
939 on targets that do not support this option. The default behaviour
940 (of not performing this garbage collection) can be restored by
941 specifying --no-gc-sections on the command line.
942 --gc-sections decides which input sections are used by examining
944 symbols and relocations. The section containing the entry symbol
945 and all sections containing symbols undefined on the command-line
946 will be kept, as will sections containing symbols referenced by
947 dynamic objects. Note that when building shared libraries, the
948 linker must assume that any visible symbol is referenced. Once
949 this initial set of sections has been determined, the linker
950 recursively marks as used any section referenced by their
951 relocations. See --entry and --undefined.
952 This option can be set when doing a partial link (enabled with
954 option -r). In this case the root of symbols kept must be
955 explicitely specified either by an --entry or --undefined option or
956 by a "ENTRY" command in the linker script.
957 --print-gc-sections
959 --no-print-gc-sections
960 List all sections removed by garbage collection. The listing is
961 printed on stderr. This option is only effective if garbage
962 collection has been enabled via the --gc-sections) option. The
963 default behaviour (of not listing the sections that are removed)
964 can be restored by specifying --no-print-gc-sections on the command
965 line.
966 --help
968 Print a summary of the command-line options on the standard output
969 and exit.
970 --target-help
972 Print a summary of all target specific options on the standard
973 output and exit.
974 -Map=mapfile
976 Print a link map to the file mapfile. See the description of the
977 -M option, above.
978 --no-keep-memory
980 ld normally optimizes for speed over memory usage by caching the
981 symbol tables of input files in memory. This option tells ld to
982 instead optimize for memory usage, by rereading the symbol tables
983 as necessary. This may be required if ld runs out of memory space
984 while linking a large executable.
985 --no-undefined
987 -z defs
988 Report unresolved symbol references from regular object files.
989 This is done even if the linker is creating a non-symbolic shared
990 library. The switch --[no-]allow-shlib-undefined controls the
991 behaviour for reporting unresolved references found in shared
992 libraries being linked in.
993 --allow-multiple-definition
995 -z muldefs
996 Normally when a symbol is defined multiple times, the linker will
997 report a fatal error. These options allow multiple definitions and
998 the first definition will be used.
999 --allow-shlib-undefined
1001 --no-allow-shlib-undefined
1002 Allows or disallows undefined symbols in shared libraries. This
1003 switch is similar to --no-undefined except that it determines the
1004 behaviour when the undefined symbols are in a shared library rather
1005 than a regular object file. It does not affect how undefined
1006 symbols in regular object files are handled.
1007 The default behaviour is to report errors for any undefined symbols
1009 referenced in shared libraries if the linker is being used to
1010 create an executable, but to allow them if the linker is being used
1011 to create a shared library.
1012 The reasons for allowing undefined symbol references in shared
1014 libraries specified at link time are that:
1015 · A shared library specified at link time may not be the same as
1017 the one that is available at load time, so the symbol might
1018 actually be resolvable at load time.
1019 · There are some operating systems, eg BeOS and HPPA, where
1021 undefined symbols in shared libraries are normal.
1022 The BeOS kernel for example patches shared libraries at load
1024 time to select whichever function is most appropriate for the
1025 current architecture. This is used, for example, to
1026 dynamically select an appropriate memset function.
1027 --no-undefined-version
1029 Normally when a symbol has an undefined version, the linker will
1030 ignore it. This option disallows symbols with undefined version and
1031 a fatal error will be issued instead.
1032 --default-symver
1034 Create and use a default symbol version (the soname) for
1035 unversioned exported symbols.
1036 --default-imported-symver
1038 Create and use a default symbol version (the soname) for
1039 unversioned imported symbols.
1040 --no-warn-mismatch
1042 Normally ld will give an error if you try to link together input
1043 files that are mismatched for some reason, perhaps because they
1044 have been compiled for different processors or for different
1045 endiannesses. This option tells ld that it should silently permit
1046 such possible errors. This option should only be used with care,
1047 in cases when you have taken some special action that ensures that
1048 the linker errors are inappropriate.
1049 --no-warn-search-mismatch
1051 Normally ld will give a warning if it finds an incompatible library
1052 during a library search. This option silences the warning.
1053 --no-whole-archive
1055 Turn off the effect of the --whole-archive option for subsequent
1056 archive files.
1057 --noinhibit-exec
1059 Retain the executable output file whenever it is still usable.
1060 Normally, the linker will not produce an output file if it
1061 encounters errors during the link process; it exits without writing
1062 an output file when it issues any error whatsoever.
1063 -nostdlib
1065 Only search library directories explicitly specified on the command
1066 line. Library directories specified in linker scripts (including
1067 linker scripts specified on the command line) are ignored.
1068 --oformat=output-format
1070 ld may be configured to support more than one kind of object file.
1071 If your ld is configured this way, you can use the --oformat option
1072 to specify the binary format for the output object file. Even when
1073 ld is configured to support alternative object formats, you don't
1074 usually need to specify this, as ld should be configured to produce
1075 as a default output format the most usual format on each machine.
1076 output-format is a text string, the name of a particular format
1077 supported by the BFD libraries. (You can list the available binary
1078 formats with objdump -i.) The script command "OUTPUT_FORMAT" can
1079 also specify the output format, but this option overrides it.
1080 -pie
1082 --pic-executable
1083 Create a position independent executable. This is currently only
1084 supported on ELF platforms. Position independent executables are
1085 similar to shared libraries in that they are relocated by the
1086 dynamic linker to the virtual address the OS chooses for them
1087 (which can vary between invocations). Like normal dynamically
1088 linked executables they can be executed and symbols defined in the
1089 executable cannot be overridden by shared libraries.
1090 -qmagic
1092 This option is ignored for Linux compatibility.
1093 -Qy This option is ignored for SVR4 compatibility.
1095 --relax
1097 An option with machine dependent effects. This option is only
1098 supported on a few targets.
1099 On some platforms, the --relax option performs global optimizations
1101 that become possible when the linker resolves addressing in the
1102 program, such as relaxing address modes and synthesizing new
1103 instructions in the output object file.
1104 On some platforms these link time global optimizations may make
1106 symbolic debugging of the resulting executable impossible. This is
1107 known to be the case for the Matsushita MN10200 and MN10300 family
1108 of processors.
1109 On platforms where this is not supported, --relax is accepted, but
1111 ignored.
1112 --retain-symbols-file=filename
1114 Retain only the symbols listed in the file filename, discarding all
1115 others. filename is simply a flat file, with one symbol name per
1116 line. This option is especially useful in environments (such as
1117 VxWorks) where a large global symbol table is accumulated
1118 gradually, to conserve run-time memory.
1119 --retain-symbols-file does not discard undefined symbols, or
1121 symbols needed for relocations.
1122 You may only specify --retain-symbols-file once in the command
1124 line. It overrides -s and -S.
1125 -rpath=dir
1127 Add a directory to the runtime library search path. This is used
1128 when linking an ELF executable with shared objects. All -rpath
1129 arguments are concatenated and passed to the runtime linker, which
1130 uses them to locate shared objects at runtime. The -rpath option
1131 is also used when locating shared objects which are needed by
1132 shared objects explicitly included in the link; see the description
1133 of the -rpath-link option. If -rpath is not used when linking an
1134 ELF executable, the contents of the environment variable
1135 "LD_RUN_PATH" will be used if it is defined.
1136 The -rpath option may also be used on SunOS. By default, on SunOS,
1138 the linker will form a runtime search patch out of all the -L
1139 options it is given. If a -rpath option is used, the runtime
1140 search path will be formed exclusively using the -rpath options,
1141 ignoring the -L options. This can be useful when using gcc, which
1142 adds many -L options which may be on NFS mounted file systems.
1143 For compatibility with other ELF linkers, if the -R option is
1145 followed by a directory name, rather than a file name, it is
1146 treated as the -rpath option.
1147 -rpath-link=dir
1149 When using ELF or SunOS, one shared library may require another.
1150 This happens when an "ld -shared" link includes a shared library as
1151 one of the input files.
1152 When the linker encounters such a dependency when doing a non-
1154 shared, non-relocatable link, it will automatically try to locate
1155 the required shared library and include it in the link, if it is
1156 not included explicitly. In such a case, the -rpath-link option
1157 specifies the first set of directories to search. The -rpath-link
1158 option may specify a sequence of directory names either by
1159 specifying a list of names separated by colons, or by appearing
1160 multiple times.
1161 This option should be used with caution as it overrides the search
1163 path that may have been hard compiled into a shared library. In
1164 such a case it is possible to use unintentionally a different
1165 search path than the runtime linker would do.
1166 The linker uses the following search paths to locate required
1168 shared libraries:
1169 1. Any directories specified by -rpath-link options.
1171 2. Any directories specified by -rpath options. The difference
1173 between -rpath and -rpath-link is that directories specified by
1174 -rpath options are included in the executable and used at
1175 runtime, whereas the -rpath-link option is only effective at
1176 link time. Searching -rpath in this way is only supported by
1177 native linkers and cross linkers which have been configured
1178 with the --with-sysroot option.
1179 3. On an ELF system, for native linkers, if the -rpath and
1181 -rpath-link options were not used, search the contents of the
1182 environment variable "LD_RUN_PATH".
1183 4. On SunOS, if the -rpath option was not used, search any
1185 directories specified using -L options.
1186 5. For a native linker, the search the contents of the environment
1188 variable "LD_LIBRARY_PATH".
1189 6. For a native ELF linker, the directories in "DT_RUNPATH" or
1191 "DT_RPATH" of a shared library are searched for shared
1192 libraries needed by it. The "DT_RPATH" entries are ignored if
1193 "DT_RUNPATH" entries exist.
1194 7. The default directories, normally /lib and /usr/lib.
1196 8. For a native linker on an ELF system, if the file
1198 /etc/ld.so.conf exists, the list of directories found in that
1199 file.
1200 If the required shared library is not found, the linker will issue
1202 a warning and continue with the link.
1203 -shared
1205 -Bshareable
1206 Create a shared library. This is currently only supported on ELF,
1207 XCOFF and SunOS platforms. On SunOS, the linker will automatically
1208 create a shared library if the -e option is not used and there are
1209 undefined symbols in the link.
1210 --sort-common
1212 --sort-common=ascending
1213 --sort-common=descending
1214 This option tells ld to sort the common symbols by alignment in
1215 ascending or descending order when it places them in the
1216 appropriate output sections. The symbol alignments considered are
1217 sixteen-byte or larger, eight-byte, four-byte, two-byte, and one-
1218 byte. This is to prevent gaps between symbols due to alignment
1219 constraints. If no sorting order is specified, then descending
1220 order is assumed.
1221 --sort-section=name
1223 This option will apply "SORT_BY_NAME" to all wildcard section
1224 patterns in the linker script.
1225 --sort-section=alignment
1227 This option will apply "SORT_BY_ALIGNMENT" to all wildcard section
1228 patterns in the linker script.
1229 --split-by-file[=size]
1231 Similar to --split-by-reloc but creates a new output section for
1232 each input file when size is reached. size defaults to a size of 1
1233 if not given.
1234 --split-by-reloc[=count]
1236 Tries to creates extra sections in the output file so that no
1237 single output section in the file contains more than count
1238 relocations. This is useful when generating huge relocatable files
1239 for downloading into certain real time kernels with the COFF object
1240 file format; since COFF cannot represent more than 65535
1241 relocations in a single section. Note that this will fail to work
1242 with object file formats which do not support arbitrary sections.
1243 The linker will not split up individual input sections for
1244 redistribution, so if a single input section contains more than
1245 count relocations one output section will contain that many
1246 relocations. count defaults to a value of 32768.
1247 --stats
1249 Compute and display statistics about the operation of the linker,
1250 such as execution time and memory usage.
1251 --sysroot=directory
1253 Use directory as the location of the sysroot, overriding the
1254 configure-time default. This option is only supported by linkers
1255 that were configured using --with-sysroot.
1256 --traditional-format
1258 For some targets, the output of ld is different in some ways from
1259 the output of some existing linker. This switch requests ld to use
1260 the traditional format instead.
1261 For example, on SunOS, ld combines duplicate entries in the symbol
1263 string table. This can reduce the size of an output file with full
1264 debugging information by over 30 percent. Unfortunately, the SunOS
1265 "dbx" program can not read the resulting program ("gdb" has no
1266 trouble). The --traditional-format switch tells ld to not combine
1267 duplicate entries.
1268 --section-start=sectionname=org
1270 Locate a section in the output file at the absolute address given
1271 by org. You may use this option as many times as necessary to
1272 locate multiple sections in the command line. org must be a single
1273 hexadecimal integer; for compatibility with other linkers, you may
1274 omit the leading 0x usually associated with hexadecimal values.
1275 Note: there should be no white space between sectionname, the
1276 equals sign ("="), and org.
1277 -Tbss=org
1279 -Tdata=org
1280 -Ttext=org
1281 Same as --section-start, with ".bss", ".data" or ".text" as the
1282 sectionname.
1283 -Ttext-segment=org
1285 When creating an ELF executable or shared object, it will set the
1286 address of the first byte of the text segment.
1287 --unresolved-symbols=method
1289 Determine how to handle unresolved symbols. There are four
1290 possible values for method:
1291 ignore-all
1293 Do not report any unresolved symbols.
1294 report-all
1296 Report all unresolved symbols. This is the default.
1297 ignore-in-object-files
1299 Report unresolved symbols that are contained in shared
1300 libraries, but ignore them if they come from regular object
1301 files.
1302 ignore-in-shared-libs
1304 Report unresolved symbols that come from regular object files,
1305 but ignore them if they come from shared libraries. This can
1306 be useful when creating a dynamic binary and it is known that
1307 all the shared libraries that it should be referencing are
1308 included on the linker's command line.
1309 The behaviour for shared libraries on their own can also be
1311 controlled by the --[no-]allow-shlib-undefined option.
1312 Normally the linker will generate an error message for each
1314 reported unresolved symbol but the option --warn-unresolved-symbols
1315 can change this to a warning.
1316 --dll-verbose
1318 --verbose
1319 Display the version number for ld and list the linker emulations
1320 supported. Display which input files can and cannot be opened.
1321 Display the linker script being used by the linker.
1322 --version-script=version-scriptfile
1324 Specify the name of a version script to the linker. This is
1325 typically used when creating shared libraries to specify additional
1326 information about the version hierarchy for the library being
1327 created. This option is only fully supported on ELF platforms
1328 which support shared libraries; see VERSION. It is partially
1329 supported on PE platforms, which can use version scripts to filter
1330 symbol visibility in auto-export mode: any symbols marked local in
1331 the version script will not be exported.
1332 --warn-common
1334 Warn when a common symbol is combined with another common symbol or
1335 with a symbol definition. Unix linkers allow this somewhat sloppy
1336 practise, but linkers on some other operating systems do not. This
1337 option allows you to find potential problems from combining global
1338 symbols. Unfortunately, some C libraries use this practise, so you
1339 may get some warnings about symbols in the libraries as well as in
1340 your programs.
1341 There are three kinds of global symbols, illustrated here by C
1343 examples:
1344 int i = 1;
1346 A definition, which goes in the initialized data section of the
1347 output file.
1348 extern int i;
1350 An undefined reference, which does not allocate space. There
1351 must be either a definition or a common symbol for the variable
1352 somewhere.
1353 int i;
1355 A common symbol. If there are only (one or more) common
1356 symbols for a variable, it goes in the uninitialized data area
1357 of the output file. The linker merges multiple common symbols
1358 for the same variable into a single symbol. If they are of
1359 different sizes, it picks the largest size. The linker turns a
1360 common symbol into a declaration, if there is a definition of
1361 the same variable.
1362 The --warn-common option can produce five kinds of warnings. Each
1364 warning consists of a pair of lines: the first describes the symbol
1365 just encountered, and the second describes the previous symbol
1366 encountered with the same name. One or both of the two symbols
1367 will be a common symbol.
1368 1. Turning a common symbol into a reference, because there is
1370 already a definition for the symbol.
1371 <file>(<section>): warning: common of `<symbol>'
1373 overridden by definition
1374 <file>(<section>): warning: defined here
1375 2. Turning a common symbol into a reference, because a later
1377 definition for the symbol is encountered. This is the same as
1378 the previous case, except that the symbols are encountered in a
1379 different order.
1380 <file>(<section>): warning: definition of `<symbol>'
1382 overriding common
1383 <file>(<section>): warning: common is here
1384 3. Merging a common symbol with a previous same-sized common
1386 symbol.
1387 <file>(<section>): warning: multiple common
1389 of `<symbol>'
1390 <file>(<section>): warning: previous common is here
1391 4. Merging a common symbol with a previous larger common symbol.
1393 <file>(<section>): warning: common of `<symbol>'
1395 overridden by larger common
1396 <file>(<section>): warning: larger common is here
1397 5. Merging a common symbol with a previous smaller common symbol.
1399 This is the same as the previous case, except that the symbols
1400 are encountered in a different order.
1401 <file>(<section>): warning: common of `<symbol>'
1403 overriding smaller common
1404 <file>(<section>): warning: smaller common is here
1405 --warn-constructors
1407 Warn if any global constructors are used. This is only useful for
1408 a few object file formats. For formats like COFF or ELF, the
1409 linker can not detect the use of global constructors.
1410 --warn-multiple-gp
1412 Warn if multiple global pointer values are required in the output
1413 file. This is only meaningful for certain processors, such as the
1414 Alpha. Specifically, some processors put large-valued constants in
1415 a special section. A special register (the global pointer) points
1416 into the middle of this section, so that constants can be loaded
1417 efficiently via a base-register relative addressing mode. Since
1418 the offset in base-register relative mode is fixed and relatively
1419 small (e.g., 16 bits), this limits the maximum size of the constant
1420 pool. Thus, in large programs, it is often necessary to use
1421 multiple global pointer values in order to be able to address all
1422 possible constants. This option causes a warning to be issued
1423 whenever this case occurs.
1424 --warn-once
1426 Only warn once for each undefined symbol, rather than once per
1427 module which refers to it.
1428 --warn-section-align
1430 Warn if the address of an output section is changed because of
1431 alignment. Typically, the alignment will be set by an input
1432 section. The address will only be changed if it not explicitly
1433 specified; that is, if the "SECTIONS" command does not specify a
1434 start address for the section.
1435 --warn-shared-textrel
1437 Warn if the linker adds a DT_TEXTREL to a shared object.
1438 --warn-alternate-em
1440 Warn if an object has alternate ELF machine code.
1441 --warn-unresolved-symbols
1443 If the linker is going to report an unresolved symbol (see the
1444 option --unresolved-symbols) it will normally generate an error.
1445 This option makes it generate a warning instead.
1446 --error-unresolved-symbols
1448 This restores the linker's default behaviour of generating errors
1449 when it is reporting unresolved symbols.
1450 --whole-archive
1452 For each archive mentioned on the command line after the
1453 --whole-archive option, include every object file in the archive in
1454 the link, rather than searching the archive for the required object
1455 files. This is normally used to turn an archive file into a shared
1456 library, forcing every object to be included in the resulting
1457 shared library. This option may be used more than once.
1458 Two notes when using this option from gcc: First, gcc doesn't know
1460 about this option, so you have to use -Wl,-whole-archive. Second,
1461 don't forget to use -Wl,-no-whole-archive after your list of
1462 archives, because gcc will add its own list of archives to your
1463 link and you may not want this flag to affect those as well.
1464 --wrap=symbol
1466 Use a wrapper function for symbol. Any undefined reference to
1467 symbol will be resolved to "__wrap_symbol". Any undefined
1468 reference to "__real_symbol" will be resolved to symbol.
1469 This can be used to provide a wrapper for a system function. The
1471 wrapper function should be called "__wrap_symbol". If it wishes to
1472 call the system function, it should call "__real_symbol".
1473 Here is a trivial example:
1475 void *
1477 __wrap_malloc (size_t c)
1478 {
1479 printf ("malloc called with %zu\n", c);
1480 return __real_malloc (c);
1481 }
1482 If you link other code with this file using --wrap malloc, then all
1484 calls to "malloc" will call the function "__wrap_malloc" instead.
1485 The call to "__real_malloc" in "__wrap_malloc" will call the real
1486 "malloc" function.
1487 You may wish to provide a "__real_malloc" function as well, so that
1489 links without the --wrap option will succeed. If you do this, you
1490 should not put the definition of "__real_malloc" in the same file
1491 as "__wrap_malloc"; if you do, the assembler may resolve the call
1492 before the linker has a chance to wrap it to "malloc".
1493 --eh-frame-hdr
1495 Request creation of ".eh_frame_hdr" section and ELF
1496 "PT_GNU_EH_FRAME" segment header.
1497 --enable-new-dtags
1499 --disable-new-dtags
1500 This linker can create the new dynamic tags in ELF. But the older
1501 ELF systems may not understand them. If you specify
1502 --enable-new-dtags, the dynamic tags will be created as needed. If
1503 you specify --disable-new-dtags, no new dynamic tags will be
1504 created. By default, the new dynamic tags are not created. Note
1505 that those options are only available for ELF systems.
1506 --hash-size=number
1508 Set the default size of the linker's hash tables to a prime number
1509 close to number. Increasing this value can reduce the length of
1510 time it takes the linker to perform its tasks, at the expense of
1511 increasing the linker's memory requirements. Similarly reducing
1512 this value can reduce the memory requirements at the expense of
1513 speed.
1514 --hash-style=style
1516 Set the type of linker's hash table(s). style can be either "sysv"
1517 for classic ELF ".hash" section, "gnu" for new style GNU
1518 ".gnu.hash" section or "both" for both the classic ELF ".hash" and
1519 new style GNU ".gnu.hash" hash tables. The default is "sysv".
1520 --reduce-memory-overheads
1522 This option reduces memory requirements at ld runtime, at the
1523 expense of linking speed. This was introduced to select the old
1524 O(n^2) algorithm for link map file generation, rather than the new
1525 O(n) algorithm which uses about 40% more memory for symbol storage.
1526 Another effect of the switch is to set the default hash table size
1528 to 1021, which again saves memory at the cost of lengthening the
1529 linker's run time. This is not done however if the --hash-size
1530 switch has been used.
1531 The --reduce-memory-overheads switch may be also be used to enable
1533 other tradeoffs in future versions of the linker.
1534 --build-id
1536 --build-id=style
1537 Request creation of ".note.gnu.build-id" ELF note section. The
1538 contents of the note are unique bits identifying this linked file.
1539 style can be "uuid" to use 128 random bits, "sha1" to use a 160-bit
1540 SHA1 hash on the normative parts of the output contents, "md5" to
1541 use a 128-bit MD5 hash on the normative parts of the output
1542 contents, or "0xhexstring" to use a chosen bit string specified as
1543 an even number of hexadecimal digits ("-" and ":" characters
1544 between digit pairs are ignored). If style is omitted, "sha1" is
1545 used.
1546 The "md5" and "sha1" styles produces an identifier that is always
1548 the same in an identical output file, but will be unique among all
1549 nonidentical output files. It is not intended to be compared as a
1550 checksum for the file's contents. A linked file may be changed
1551 later by other tools, but the build ID bit string identifying the
1552 original linked file does not change.
1553 Passing "none" for style disables the setting from any "--build-id"
1555 options earlier on the command line.
1556 The i386 PE linker supports the -shared option, which causes the output
1558 to be a dynamically linked library (DLL) instead of a normal
1559 executable. You should name the output "*.dll" when you use this
1560 option. In addition, the linker fully supports the standard "*.def"
1561 files, which may be specified on the linker command line like an object
1562 file (in fact, it should precede archives it exports symbols from, to
1563 ensure that they get linked in, just like a normal object file).
1564 In addition to the options common to all targets, the i386 PE linker
1566 support additional command line options that are specific to the i386
1567 PE target. Options that take values may be separated from their values
1568 by either a space or an equals sign.
1569 --add-stdcall-alias
1571 If given, symbols with a stdcall suffix (@nn) will be exported as-
1572 is and also with the suffix stripped. [This option is specific to
1573 the i386 PE targeted port of the linker]
1574 --base-file file
1576 Use file as the name of a file in which to save the base addresses
1577 of all the relocations needed for generating DLLs with dlltool.
1578 [This is an i386 PE specific option]
1579 --dll
1581 Create a DLL instead of a regular executable. You may also use
1582 -shared or specify a "LIBRARY" in a given ".def" file. [This
1583 option is specific to the i386 PE targeted port of the linker]
1584 --enable-long-section-names
1586 --disable-long-section-names
1587 The PE variants of the Coff object format add an extension that
1588 permits the use of section names longer than eight characters, the
1589 normal limit for Coff. By default, these names are only allowed in
1590 object files, as fully-linked executable images do not carry the
1591 Coff string table required to support the longer names. As a GNU
1592 extension, it is possible to allow their use in executable images
1593 as well, or to (probably pointlessly!) disallow it in object
1594 files, by using these two options. Executable images generated
1595 with these long section names are slightly non-standard, carrying
1596 as they do a string table, and may generate confusing output when
1597 examined with non-GNU PE-aware tools, such as file viewers and
1598 dumpers. However, GDB relies on the use of PE long section names
1599 to find Dwarf-2 debug information sections in an executable image
1600 at runtime, and so if neither option is specified on the command-
1601 line, ld will enable long section names, overriding the default and
1602 technically correct behaviour, when it finds the presence of debug
1603 information while linking an executable image and not stripping
1604 symbols. [This option is valid for all PE targeted ports of the
1605 linker]
1606 --enable-stdcall-fixup
1608 --disable-stdcall-fixup
1609 If the link finds a symbol that it cannot resolve, it will attempt
1610 to do "fuzzy linking" by looking for another defined symbol that
1611 differs only in the format of the symbol name (cdecl vs stdcall)
1612 and will resolve that symbol by linking to the match. For example,
1613 the undefined symbol "_foo" might be linked to the function
1614 "_foo@12", or the undefined symbol "_bar@16" might be linked to the
1615 function "_bar". When the linker does this, it prints a warning,
1616 since it normally should have failed to link, but sometimes import
1617 libraries generated from third-party dlls may need this feature to
1618 be usable. If you specify --enable-stdcall-fixup, this feature is
1619 fully enabled and warnings are not printed. If you specify
1620 --disable-stdcall-fixup, this feature is disabled and such
1621 mismatches are considered to be errors. [This option is specific
1622 to the i386 PE targeted port of the linker]
1623 --export-all-symbols
1625 If given, all global symbols in the objects used to build a DLL
1626 will be exported by the DLL. Note that this is the default if
1627 there otherwise wouldn't be any exported symbols. When symbols are
1628 explicitly exported via DEF files or implicitly exported via
1629 function attributes, the default is to not export anything else
1630 unless this option is given. Note that the symbols "DllMain@12",
1631 "DllEntryPoint@0", "DllMainCRTStartup@12", and "impure_ptr" will
1632 not be automatically exported. Also, symbols imported from other
1633 DLLs will not be re-exported, nor will symbols specifying the DLL's
1634 internal layout such as those beginning with "_head_" or ending
1635 with "_iname". In addition, no symbols from "libgcc", "libstd++",
1636 "libmingw32", or "crtX.o" will be exported. Symbols whose names
1637 begin with "__rtti_" or "__builtin_" will not be exported, to help
1638 with C++ DLLs. Finally, there is an extensive list of cygwin-
1639 private symbols that are not exported (obviously, this applies on
1640 when building DLLs for cygwin targets). These cygwin-excludes are:
1641 "_cygwin_dll_entry@12", "_cygwin_crt0_common@8",
1642 "_cygwin_noncygwin_dll_entry@12", "_fmode", "_impure_ptr",
1643 "cygwin_attach_dll", "cygwin_premain0", "cygwin_premain1",
1644 "cygwin_premain2", "cygwin_premain3", and "environ". [This option
1645 is specific to the i386 PE targeted port of the linker]
1646 --exclude-symbols symbol,symbol,...
1648 Specifies a list of symbols which should not be automatically
1649 exported. The symbol names may be delimited by commas or colons.
1650 [This option is specific to the i386 PE targeted port of the
1651 linker]
1652 --file-alignment
1654 Specify the file alignment. Sections in the file will always begin
1655 at file offsets which are multiples of this number. This defaults
1656 to 512. [This option is specific to the i386 PE targeted port of
1657 the linker]
1658 --heap reserve
1660 --heap reserve,commit
1661 Specify the number of bytes of memory to reserve (and optionally
1662 commit) to be used as heap for this program. The default is 1Mb
1663 reserved, 4K committed. [This option is specific to the i386 PE
1664 targeted port of the linker]
1665 --image-base value
1667 Use value as the base address of your program or dll. This is the
1668 lowest memory location that will be used when your program or dll
1669 is loaded. To reduce the need to relocate and improve performance
1670 of your dlls, each should have a unique base address and not
1671 overlap any other dlls. The default is 0x400000 for executables,
1672 and 0x10000000 for dlls. [This option is specific to the i386 PE
1673 targeted port of the linker]
1674 --kill-at
1676 If given, the stdcall suffixes (@nn) will be stripped from symbols
1677 before they are exported. [This option is specific to the i386 PE
1678 targeted port of the linker]
1679 --large-address-aware
1681 If given, the appropriate bit in the "Characteristics" field of the
1682 COFF header is set to indicate that this executable supports
1683 virtual addresses greater than 2 gigabytes. This should be used in
1684 conjunction with the /3GB or /USERVA=value megabytes switch in the
1685 "[operating systems]" section of the BOOT.INI. Otherwise, this bit
1686 has no effect. [This option is specific to PE targeted ports of
1687 the linker]
1688 --major-image-version value
1690 Sets the major number of the "image version". Defaults to 1.
1691 [This option is specific to the i386 PE targeted port of the
1692 linker]
1693 --major-os-version value
1695 Sets the major number of the "os version". Defaults to 4. [This
1696 option is specific to the i386 PE targeted port of the linker]
1697 --major-subsystem-version value
1699 Sets the major number of the "subsystem version". Defaults to 4.
1700 [This option is specific to the i386 PE targeted port of the
1701 linker]
1702 --minor-image-version value
1704 Sets the minor number of the "image version". Defaults to 0.
1705 [This option is specific to the i386 PE targeted port of the
1706 linker]
1707 --minor-os-version value
1709 Sets the minor number of the "os version". Defaults to 0. [This
1710 option is specific to the i386 PE targeted port of the linker]
1711 --minor-subsystem-version value
1713 Sets the minor number of the "subsystem version". Defaults to 0.
1714 [This option is specific to the i386 PE targeted port of the
1715 linker]
1716 --output-def file
1718 The linker will create the file file which will contain a DEF file
1719 corresponding to the DLL the linker is generating. This DEF file
1720 (which should be called "*.def") may be used to create an import
1721 library with "dlltool" or may be used as a reference to
1722 automatically or implicitly exported symbols. [This option is
1723 specific to the i386 PE targeted port of the linker]
1724 --out-implib file
1726 The linker will create the file file which will contain an import
1727 lib corresponding to the DLL the linker is generating. This import
1728 lib (which should be called "*.dll.a" or "*.a" may be used to link
1729 clients against the generated DLL; this behaviour makes it possible
1730 to skip a separate "dlltool" import library creation step. [This
1731 option is specific to the i386 PE targeted port of the linker]
1732 --enable-auto-image-base
1734 Automatically choose the image base for DLLs, unless one is
1735 specified using the "--image-base" argument. By using a hash
1736 generated from the dllname to create unique image bases for each
1737 DLL, in-memory collisions and relocations which can delay program
1738 execution are avoided. [This option is specific to the i386 PE
1739 targeted port of the linker]
1740 --disable-auto-image-base
1742 Do not automatically generate a unique image base. If there is no
1743 user-specified image base ("--image-base") then use the platform
1744 default. [This option is specific to the i386 PE targeted port of
1745 the linker]
1746 --dll-search-prefix string
1748 When linking dynamically to a dll without an import library, search
1749 for "<string><basename>.dll" in preference to "lib<basename>.dll".
1750 This behaviour allows easy distinction between DLLs built for the
1751 various "subplatforms": native, cygwin, uwin, pw, etc. For
1752 instance, cygwin DLLs typically use "--dll-search-prefix=cyg".
1753 [This option is specific to the i386 PE targeted port of the
1754 linker]
1755 --enable-auto-import
1757 Do sophisticated linking of "_symbol" to "__imp__symbol" for DATA
1758 imports from DLLs, and create the necessary thunking symbols when
1759 building the import libraries with those DATA exports. Note: Use of
1760 the 'auto-import' extension will cause the text section of the
1761 image file to be made writable. This does not conform to the PE-
1762 COFF format specification published by Microsoft.
1763 Note - use of the 'auto-import' extension will also cause read only
1765 data which would normally be placed into the .rdata section to be
1766 placed into the .data section instead. This is in order to work
1767 around a problem with consts that is described here:
1768 http://www.cygwin.com/ml/cygwin/2004-09/msg01101.html
1769 Using 'auto-import' generally will 'just work' -- but sometimes you
1771 may see this message:
1772 "variable '<var>' can't be auto-imported. Please read the
1774 documentation for ld's "--enable-auto-import" for details."
1775 This message occurs when some (sub)expression accesses an address
1777 ultimately given by the sum of two constants (Win32 import tables
1778 only allow one). Instances where this may occur include accesses
1779 to member fields of struct variables imported from a DLL, as well
1780 as using a constant index into an array variable imported from a
1781 DLL. Any multiword variable (arrays, structs, long long, etc) may
1782 trigger this error condition. However, regardless of the exact
1783 data type of the offending exported variable, ld will always detect
1784 it, issue the warning, and exit.
1785 There are several ways to address this difficulty, regardless of
1787 the data type of the exported variable:
1788 One way is to use --enable-runtime-pseudo-reloc switch. This leaves
1790 the task of adjusting references in your client code for runtime
1791 environment, so this method works only when runtime environment
1792 supports this feature.
1793 A second solution is to force one of the 'constants' to be a
1795 variable -- that is, unknown and un-optimizable at compile time.
1796 For arrays, there are two possibilities: a) make the indexee (the
1797 array's address) a variable, or b) make the 'constant' index a
1798 variable. Thus:
1799 extern type extern_array[];
1801 extern_array[1] -->
1802 { volatile type *t=extern_array; t[1] }
1803 or
1805 extern type extern_array[];
1807 extern_array[1] -->
1808 { volatile int t=1; extern_array[t] }
1809 For structs (and most other multiword data types) the only option
1811 is to make the struct itself (or the long long, or the ...)
1812 variable:
1813 extern struct s extern_struct;
1815 extern_struct.field -->
1816 { volatile struct s *t=&extern_struct; t->field }
1817 or
1819 extern long long extern_ll;
1821 extern_ll -->
1822 { volatile long long * local_ll=&extern_ll; *local_ll }
1823 A third method of dealing with this difficulty is to abandon
1825 'auto-import' for the offending symbol and mark it with
1826 "__declspec(dllimport)". However, in practise that requires using
1827 compile-time #defines to indicate whether you are building a DLL,
1828 building client code that will link to the DLL, or merely
1829 building/linking to a static library. In making the choice
1830 between the various methods of resolving the 'direct address with
1831 constant offset' problem, you should consider typical real-world
1832 usage:
1833 Original:
1835 --foo.h
1837 extern int arr[];
1838 --foo.c
1839 #include "foo.h"
1840 void main(int argc, char **argv){
1841 printf("%d\n",arr[1]);
1842 }
1843 Solution 1:
1845 --foo.h
1847 extern int arr[];
1848 --foo.c
1849 #include "foo.h"
1850 void main(int argc, char **argv){
1851 /* This workaround is for win32 and cygwin; do not "optimize" */
1852 volatile int *parr = arr;
1853 printf("%d\n",parr[1]);
1854 }
1855 Solution 2:
1857 --foo.h
1859 /* Note: auto-export is assumed (no __declspec(dllexport)) */
1860 #if (defined(_WIN32) || defined(__CYGWIN__)) && \
1861 !(defined(FOO_BUILD_DLL) || defined(FOO_STATIC))
1862 #define FOO_IMPORT __declspec(dllimport)
1863 #else
1864 #define FOO_IMPORT
1865 #endif
1866 extern FOO_IMPORT int arr[];
1867 --foo.c
1868 #include "foo.h"
1869 void main(int argc, char **argv){
1870 printf("%d\n",arr[1]);
1871 }
1872 A fourth way to avoid this problem is to re-code your library to
1874 use a functional interface rather than a data interface for the
1875 offending variables (e.g. set_foo() and get_foo() accessor
1876 functions). [This option is specific to the i386 PE targeted port
1877 of the linker]
1878 --disable-auto-import
1880 Do not attempt to do sophisticated linking of "_symbol" to
1881 "__imp__symbol" for DATA imports from DLLs. [This option is
1882 specific to the i386 PE targeted port of the linker]
1883 --enable-runtime-pseudo-reloc
1885 If your code contains expressions described in --enable-auto-import
1886 section, that is, DATA imports from DLL with non-zero offset, this
1887 switch will create a vector of 'runtime pseudo relocations' which
1888 can be used by runtime environment to adjust references to such
1889 data in your client code. [This option is specific to the i386 PE
1890 targeted port of the linker]
1891 --disable-runtime-pseudo-reloc
1893 Do not create pseudo relocations for non-zero offset DATA imports
1894 from DLLs. This is the default. [This option is specific to the
1895 i386 PE targeted port of the linker]
1896 --enable-extra-pe-debug
1898 Show additional debug info related to auto-import symbol thunking.
1899 [This option is specific to the i386 PE targeted port of the
1900 linker]
1901 --section-alignment
1903 Sets the section alignment. Sections in memory will always begin
1904 at addresses which are a multiple of this number. Defaults to
1905 0x1000. [This option is specific to the i386 PE targeted port of
1906 the linker]
1907 --stack reserve
1909 --stack reserve,commit
1910 Specify the number of bytes of memory to reserve (and optionally
1911 commit) to be used as stack for this program. The default is 2Mb
1912 reserved, 4K committed. [This option is specific to the i386 PE
1913 targeted port of the linker]
1914 --subsystem which
1916 --subsystem which:major
1917 --subsystem which:major.minor
1918 Specifies the subsystem under which your program will execute. The
1919 legal values for which are "native", "windows", "console", "posix",
1920 and "xbox". You may optionally set the subsystem version also.
1921 Numeric values are also accepted for which. [This option is
1922 specific to the i386 PE targeted port of the linker]
1923 The following options set flags in the "DllCharacteristics" field
1925 of the PE file header: [These options are specific to PE targeted
1926 ports of the linker]
1927 --dynamicbase
1929 The image base address may be relocated using address space layout
1930 randomization (ASLR). This feature was introduced with MS Windows
1931 Vista for i386 PE targets.
1932 --forceinteg
1934 Code integrity checks are enforced.
1935 --nxcompat
1937 The image is compatible with the Data Execution Prevention. This
1938 feature was introduced with MS Windows XP SP2 for i386 PE targets.
1939 --no-isolation
1941 Although the image understands isolation, do not isolate the image.
1942 --no-seh
1944 The image does not use SEH. No SE handler may be called from this
1945 image.
1946 --no-bind
1948 Do not bind this image.
1949 --wdmdriver
1951 The driver uses the MS Windows Driver Model.
1952 --tsaware
1954 The image is Terminal Server aware.
1955 The 68HC11 and 68HC12 linkers support specific options to control the
1957 memory bank switching mapping and trampoline code generation.
1958 --no-trampoline
1960 This option disables the generation of trampoline. By default a
1961 trampoline is generated for each far function which is called using
1962 a "jsr" instruction (this happens when a pointer to a far function
1963 is taken).
1964 --bank-window name
1966 This option indicates to the linker the name of the memory region
1967 in the MEMORY specification that describes the memory bank window.
1968 The definition of such region is then used by the linker to compute
1969 paging and addresses within the memory window.
1970 The following options are supported to control handling of GOT
1972 generation when linking for 68K targets.
1973 --got=type
1975 This option tells the linker which GOT generation scheme to use.
1976 type should be one of single, negative, multigot or target. For
1977 more information refer to the Info entry for ld.
1978
1980 You can change the behaviour of ld with the environment variables
1981 "GNUTARGET", "LDEMULATION" and "COLLECT_NO_DEMANGLE".
1982 "GNUTARGET" determines the input-file object format if you don't use -b
1984 (or its synonym --format). Its value should be one of the BFD names
1985 for an input format. If there is no "GNUTARGET" in the environment, ld
1986 uses the natural format of the target. If "GNUTARGET" is set to
1987 "default" then BFD attempts to discover the input format by examining
1988 binary input files; this method often succeeds, but there are potential
1989 ambiguities, since there is no method of ensuring that the magic number
1990 used to specify object-file formats is unique. However, the
1991 configuration procedure for BFD on each system places the conventional
1992 format for that system first in the search-list, so ambiguities are
1993 resolved in favor of convention.
1994 "LDEMULATION" determines the default emulation if you don't use the -m
1996 option. The emulation can affect various aspects of linker behaviour,
1997 particularly the default linker script. You can list the available
1998 emulations with the --verbose or -V options. If the -m option is not
1999 used, and the "LDEMULATION" environment variable is not defined, the
2000 default emulation depends upon how the linker was configured.
2001 Normally, the linker will default to demangling symbols. However, if
2003 "COLLECT_NO_DEMANGLE" is set in the environment, then it will default
2004 to not demangling symbols. This environment variable is used in a
2005 similar fashion by the "gcc" linker wrapper program. The default may
2006 be overridden by the --demangle and --no-demangle options.
2007
2009 ar(1), nm(1), objcopy(1), objdump(1), readelf(1) and the Info entries
2010 for binutils and ld.
2011
2013 Copyright (c) 1991, 92, 93, 94, 95, 96, 97, 98, 99, 2000, 2001, 2002,
2014 2003, 2004, 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
2015 Permission is granted to copy, distribute and/or modify this document
2017 under the terms of the GNU Free Documentation License, Version 1.3 or
2018 any later version published by the Free Software Foundation; with no
2019 Invariant Sections, with no Front-Cover Texts, and with no Back-Cover
2020 Texts. A copy of the license is included in the section entitled "GNU
2021 Free Documentation License".
2022binutils-2.20.51.0.2 2019-02-26 LD(1)